On Wednesday, October 3, 2012 4:59:58 PM UTC-5, Tim Mooney wrote: > > > All- > > We're currently using puppet 2.7.14 on master and all clients. > > I thought I understood why 'anchor' is part of stdlib, but after > re-reading both > > > http://projects.puppetlabs.com/projects/puppet/wiki/Anchor_Pattern > > and > > http://projects.puppetlabs.com/issues/8040 > > yesterday in preparation for trying to explain it to one of our team > that's coming up to speed on puppet, now I'm not so certain I really > understand. > > Specifically, is it necessary to use the anchor pattern if your module > only defines resources and doesn't require or include any other classes? >
No, not as I understand it. The problem is that in Puppet 2.6 and maybe 2.7, classes are not directly represented in the relationship graph. Therefore, if you declare a relationship where one end is a class, it appears in the graph as a collection of relationships with the resources declared by that class. If both ends are classes then you get n x m relationships, where n and m are the numbers of resources declared by the two classes. The need for the anchor pattern arises because the generated relationships to a class Foo's resources do not include relationships to resources declared by classes declared in the body of Foo, and because declaring a class (except via the 'require' function) does not create a relationship between the declaring and declared classes. The anchor pattern involves using relationships to resources declared directly by Foo to bound the application order of classes declared by Foo. Anchors are not needed for resources declared directly by Foo (else the anchor pattern wouldn't work in the first place). The stdlib provides the special 'anchor' resource type specifically for this purpose, but resources of any other type could be used as well. If Foo does not declare any other classes, then it gains no advantage from the anchor pattern. If the needed ordering of interclass relationships is declared some other way, then the anchor pattern is unneeded. If and when classes gain direct representation in the relationship graph (maybe it's happened already?), with (optional?) relationships to their included classes, the anchor pattern will no longer be needed. John -- You received this message because you are subscribed to the Google Groups "Puppet Users" group. To view this discussion on the web visit https://groups.google.com/d/msg/puppet-users/-/ADbfiab83rMJ. To post to this group, send email to puppet-users@googlegroups.com. To unsubscribe from this group, send email to puppet-users+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/puppet-users?hl=en.
